BIOL 1000 Lecture 2: Membranes and Membrane Transport

43 views3 pages

pucegoat339

21 Feb 2019

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

Selective permeability: membranes that selectively allow impede, or block the passage of atoms and molecules. Diffusion: the net movement of ions or molecules from a region of higher concentration to a region of lower concentration. Gradient: the change in concentration of a substance over distance or across a membrane. Channel protein: transport protein that forms a hydrophilic channel in a cell membrane through which water, ions, or other molecules can pass depending on the protein. Carrier protein: transport protein that binds a specific single solute and transports it across the lipid bilayer. Integral protein: a protein that is attached to the phospholipid bilayer. Peripheral protein: protein held to membrane surfaces by non-covalent bonds formed with the polar parts of integral membrane proteins or membrane lipids. Active transport: mechanism by which ions and molecules move against the concentration gradient across a membrane, from the side with the lower concentration to the side with the higher concentration.

Related Questions

During active transport in the neuron, the outside of the cell is _________________ and the inside is _______________.

positive, negative

more positive, less positive

more negative, less negative

negative, positive

In active transport, _____________ provides the energy to move molecules against their concentration gradient.

nucleus

potassium

sodium

adenosine triphosphate

________________ proteins can change shape when moving substances across the membrane.

Proteins that can be open or closed, based on different conditions, are called ___________.

bypass proteins

channel proteins

selective proteins

gated

Tunnels that allow charged ions to move easily across the plasma membrane without the use of energy are called ____________________.

channel proteins

glycolypipd proteins

phospholipid proteins

carbohydrate chains

____________ and ____________ make it easier for molecules to move across the plasma membrane.

small, negatively charged

small, positively charged

small, no charge

large, negatively charged

large, positively charged

Cellular biology answer check. please check if my answers arecorrect or not.

1) The concentration of ions inside a cell is the same as theirconcentration outside of the cell. True or false? (i chose falsesince having equilibrium inside a cell is bad)

2) Membrane transport proteins...

a)...transport membrane potentials between cells

b)	...transport membranes from the ER to the Golgi

c)	...are made up of phospholipids

d)	...transport molecules across membranes

i chose d

3)The electrochemical gradienttakes into account:

a)	The concentration of solutes on either side of themembrane.

b)	The overall charge on either side of the membrane.

c)	Both of these.

i chose C. (although i am sure that overall charge matters, Iwasn't sure if concentration of solutes are taken account.)

4) If no energywere expended by an animal cell:

a)	Both gradients would be depleted

b)The K+ gradient would maintain itself.

c)	None of these

d)	The Na+ gradient would maintain itself.

I chose d) mainly because I think Na+ gradient exist in animalcell and not K+ gradient.

5) Which of the following is a true statement aboutactin?

a)	Once actin has polymerized, it never depolymerizes.

b)	Actin is a transmembrane protein.

c)	Actin can form branched networks.

d)	Actin filaments are organized into hollow tubes.

I chose c. can't explain why.

6)Ion channels:

a)	Form a hydrophobic channel through the membrane

b)	Have filters that let sugars through

c)	Are selective for particular ions (only the

taupeshark376

1. To move molecules from a low concentration on one side of amembrane to a high concentration on the other side of a membrane,which would be needed?
A.
Time
B.
A protein that can engage in facilitated diffusion
C.
An active (energy-requiring) process that moves the moleculesdirectly rather than relying on diffusion

Answer choice c

2. If a cell transports a number of these ions across the membrane,which direction of transport would require energy from thecell?
A.
From the outside to the inside of the cell
B.
From the inside to the outside of the cell

Answer choice A

3. Which of the following is not true of the carrier moleculesinvolved in
facilitated diffusion?

A.
They do not require energy to operate.
B.
They can concentrate molecules on one side of the membrane.
C.
They allow molecules to travel both directions across amembrane.
D.
They may undergo a structural (conformational) change upon bindinga molecule.

Answer choice D

BIOL 1000 Lecture 2: Membranes and Membrane Transport

Document Summary

Get access

Related Documents

BIOL 1000 Study Guide - Midterm Guide: Radio-Frequency Identification, Tonicity, Nuclear Membrane

BIOL 1000 Chapter Notes - Chapter 5: Lipid Bilayer, Cell Membrane, Membrane Transport Protein

BIOL 1000 Chapter Notes - Chapter 5: Transmembrane Protein, Lipid Bilayer, Adenylyl Cyclase

Related Questions